This invention relates to the field of medical devices. More specifically, this invention relates to the field of needleless valve connectors that may be used with medical devices such as catheters, especially intravascular (IV) catheters, IV administration sets, syringes and medicine vials.
In the treatment of patients, valve connectors are needed to facilitate the transfer of fluids between various containers and IV lines or through IV catheters into the patient. For example, where an IV catheter has been placed into a patient to gain access to the patient's vasculature, it may be necessary to infuse medicament through the IV catheter into the patient or to withdraw blood from the patient for blood gas or other analysis. Previously, a rubber or silicone septum was located over the proximal opening in the catheter adapter which prevents blood from flowing out of the catheter but allows the clinician to insert the sharp needle from a standard hypodermic syringe therethrough to infuse fluid from the syringe through the catheter and into the patient or to withdraw fluid into the syringe from the patient. The septum reseals when the needle is withdrawn to thereby prevent back flow of fluid.
In recent years, concern has grown about the risks of infection from diseases such as hepatitis and AIDS (Acquired Immuno-Deficiency Syndrome) that can be spread by the exchange of body fluids via contaminated needles. As a result, much effort has been expended in developing various valve connectors that avoid the use of sharp needles.
One approach has been the development of a needleless valve connector that can be accessed by the blunt male luer tip of a medical device such as a typical syringe. Such a needleless valve connector includes a longitudinally movable diaphragm that controls the flow of fluid through an internal cannula fixed in the needleless valve connector. This internal cannula defines the fluid flow path through the needleless valve connector. The movable diaphragm cooperates with a biasing member such as a spring or other flexible member that biases the top of the movable diaphragm toward the inlet or proximal opening to the needleless valve connector. The opening is typically in the form of a female luer adapter. When the movable diaphragm is adjacent to the inlet of the needleless valve connector, the movable diaphragm occludes the opening to the internal cannula effectively closing the needleless valve connector to fluid flow. When the clinician inserts the male luer tip of the syringe into the female luer adapter of the needieless valve connector, the movable diaphragm is pushed down therein so the internal cannula extends through a pre-formed slit in the movable diaphragm providing a fluid flow path through the needleless valve connector.
It is desirable for the top of the movable diaphragm to be generally flush with the opening to the needleless valve connector so the clinician can swab the top of the movable diaphragm with a disinfectant. This reduces the risk that infection-causing organisms will be infused into the patient when the male luer tip of a medical device contacts the top of the movable diaphragm to move the diaphragm down to open the needleless valve connector and fluid is infused from the syringe through the needleless valve connector.
Although such needleless valve connectors generally perform in accordance with their intended purposes, they could be improved. For example, when the tip of the internal cannula engages the movable diaphragm, the internal cannula has a tendency to core the movable diaphragm. This may cause pieces of the movable diaphragm to be broken off and potentially infused into a patient. In addition, this coring of the movable diaphragm promotes fluid leakage of the needieless valve connector. Finally, the force needed to move the movable diaphragm past the tip of the internal cannula can be quite high making it difficult to operate.